They usually have a mechanism that attaches to whatever button makes them work, or the mechanism is built into it... Hard to explain without popping one apart, but I'd suggest (If it's in your budget) to pop open a Kit Fisto sometime.

His action feature arm (Though a well hidden feature that didn't itself hurt the figure) is really different than his normal arm.

As for the Clone Head, I haven't ever popped one apart to say one way or the other. I know it's a strange articulation style compared to how other ball/socket necks have been for Hasbro figures. The latest Dooku was different too, and the Clone and Dooku don't look as nice as say the Concept Stormtrooper or Clone Pilot's joints look.

From my experience so far in popping the arms of "action feature plagued" figures is that the "joint" for the arms is obviously not a normal peg, but it is still the general shape of a peg and with a little cutting and sanding you can get a nice arm to work with. Case in point the left arm for Kit Fitso, I used his arms to make a better Mace Windu, but the left arm was so screwy, the "peg" for the action feature was soooo huge, so I had to do a lot cutting and sanding just to get a good general shape, but once I did get the shape I was looking for, it looked nice and smooth against the Mace torso. I agree with JJ, if you got an extra $2 head on over to KB and grab a Kit and just take him apart and experiment with him, you could get some nice results.